Ovarian cancer is often diagnosed at an advanced stage because its initial symptoms are vague, but early detection significantly improves survival rates, making effective diagnostic tools important. While no single test exists for widespread screening, a Computed Tomography (CT) scan is a valuable imaging modality used to investigate suspected cases and determine the extent of the disease. This article clarifies the role and utility of CT scans in diagnosing and managing ovarian cancer.
How Computed Tomography Scans Are Used in Ovarian Cancer Assessment
A CT scan uses X-rays and computer processing to create detailed cross-sectional images of the body, providing a clear view of soft tissues, organs, and bones. The CT scan is generally not employed as a primary screening tool for women without symptoms. When ovarian cancer is suspected, often following initial tests, the CT scan becomes a crucial investigative and staging instrument.
The primary contribution of the CT scan is precisely assessing the extent of cancer spread, known as staging. By visualizing the entire abdomen and pelvis, the scan can detect tumors and metastasis to distant sites, such as the liver, lungs, or lymph nodes. This comprehensive mapping is vital for surgical planning, helping the oncologist determine if the tumor is resectable and identifying critical surrounding anatomy.
CT scans are also used to monitor the disease’s response to treatment, particularly chemotherapy administered before surgery (neoadjuvant chemotherapy). Regular scans allow physicians to track changes in tumor size and the extent of spread, indicating whether the current therapeutic approach is effective. The scan’s ability to clearly visualize soft tissue makes it a strong tool for follow-up and detecting potential recurrence.
The Primary Tools for Initial Detection
When symptoms suggest ovarian cancer, the initial assessment focuses on two diagnostic methods before a CT scan is ordered. The first is the Transvaginal Ultrasound (TVUS), which is often the first imaging test performed. The TVUS uses sound waves to generate detailed images of the ovaries, allowing doctors to evaluate the characteristics of any masses found.
The ultrasound helps determine if a mass is simple and fluid-filled, suggesting a benign cyst, or if it is complex with solid components, irregular borders, or internal partitions, which are features concerning for malignancy. The second tool is a blood test that measures the level of Cancer Antigen 125 (CA-125), a protein that can be elevated in the presence of ovarian cancer.
CA-125 is not a perfect test because its levels can be raised by non-cancerous conditions like endometriosis, and it is only elevated in about half of early-stage ovarian cancer cases. These initial tests assess the likelihood of cancer, guiding the decision to proceed with more detailed imaging like the CT scan. For high-risk women, regular CA-125 testing and TVUS may be recommended for surveillance.
Specific Signs of Ovarian Cancer on a CT Scan
When a radiologist examines a CT scan, they look for visual cues related to both the primary mass and metastatic disease. A benign ovarian cyst typically appears as a simple, thin-walled, fluid-filled structure. In contrast, a mass concerning for cancer often displays complex features such as solid components, thick or irregular walls, or internal divisions (septations).
The CT scan excels at identifying signs of cancer spread outside of the ovary. One common finding in advanced ovarian cancer is ascites, the accumulation of abnormal fluid within the abdominal cavity. Ascites appears as a dark, uniform area surrounding the organs on the scan and is a strong indicator of advanced disease.
The scan also reveals signs of peritoneal disease, which involves small tumor deposits or nodules on the lining of the abdominal cavity (the peritoneum). The radiologist also looks for enlarged lymph nodes in the pelvic and abdominal areas (lymphadenopathy), indicating cancer spread through the lymphatic system. The combination of a complex ovarian mass with these signs provides a highly suspicious picture of malignancy.
Moving Beyond Imaging: Definitive Diagnosis
While a CT scan provides an extensive map of the disease and strongly suggests ovarian cancer, it cannot offer a definitive diagnosis. Imaging tests only provide visual evidence and cannot distinguish between a malignant tumor and a benign condition that mimics its appearance. The only way to confirm malignancy, determine the specific cancer type, and guide treatment is through a tissue sample.
The tissue sample is obtained through a biopsy, where a small piece of suspicious tissue is removed and examined by a pathologist. If the CT scan suggests widespread disease that is not immediately operable, an image-guided needle biopsy may be performed. The CT scan can precisely guide the needle to the target area, ensuring the sample is taken from the most representative part of the tumor.
More commonly, definitive diagnosis and staging occur during the initial surgical procedure (cytoreductive or debulking surgery). The surgeon removes the primary tumor and any visible sites of spread, and the tissue is immediately sent for pathological analysis. Consulting with a gynecologic oncologist after a CT scan shows concerning results is an important step to plan the transition to tissue-based confirmation and treatment.